Communication lines are used in a wide range of applications in the oilfield industry. The communication lines transmit monitored data regarding downhole conditions such as temperature and pressure to surface instrumentation. The communication lines can also be used to send information down the well from the surface. Additionally, communication lines may also be used to electrically power downhole equipment. Communication lines may include electrical conduits, optical fibers, hydraulic lines and other methods for data or power transmission. Hybrid cables may include multiple types of communication lines in the same cable package, e.g., both electrical conductors and optical fibers.
In environments such as those encountered in downhole wells, the communication lines are exposed to hostile conditions such as elevated temperatures and pressures. To protect the fragile communication lines from the hostile conditions, the communication lines are generally carried within protective tubing that provides an environmental seal. Problems arise when the seal must be broken during assembly, installation and/or repair of the communication line. For example, in downhole applications, in order for the communication line to be fed through production equipment such as packers, the line must be cut and then spliced with the downstream line. Thus, after splicing, the communication line must once again be sealed from the harsh environment.
Hybrid cables may contain multiple optical fibers that may need to be spliced. For example, c conventional fusion splicing requires each optical fiber to be separately prepared (e.g., cutting to length, stripping the buffer material, cleaving, cleaning, etc.) and then separately fusion spliced. Each fusion splice multiplies the time it takes to complete the assembly, often at the expense of valuable rig time and adding to the installer's fatigue, which increases the installation risk. Moreover, in space restricted packaging configurations, such as hybrid cables, the individual spliced fibers typically need to be kept to near identical lengths. Therefore, all the individual fusion splices need to be successful (e.g., free of flaws and with low optical loss), or otherwise all the fibers will need to be restored to the same length, thereby necessitating breaking any previously successful splices. In addition to the lost time, the process of redoing the splices may move the position of the assembly to the detriment of the completion design, or even result in insufficient cable length to complete the assembly.
Therefore, there is a need for a method of splicing hybrid cables and an apparatus for protecting the hybrid splice from the surrounding environment.